This is the Earth from Saturn. Taken July 19, 2013
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Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam." - Carl Sagan

^^That's NGC 3185. It's a Seyfert barred spiral galaxy whose central black hole (all galaxies have them) is active, going through a binge-and-purge cycle where it's gobbling so much gas that most of it heats up and spews back into space before it can fall in to the black hole forever. That's why the central part of the galaxy is so bright. Our galaxy has a much quieter nucleus, happily.

Check this out--our galaxy is a large barred spiral at least 100,000 light years in diameter, which is pretty huge for a spiral. Some are even bigger, though; this is NGC 6744, 175,000 light years wide and one of the largest spirals known. Better yet, it looks exactly like how most astronomers think the Milky Way looks, with a central bar, ring structure, and arms coming from that. Have a look at a galaxy just like yours, humans (and at 30 million light years away, only in the next town over).

Yes, they all do, and astronomers have discovered a direct correlation between the mass of the black hole, the size of the galaxy's nucleus, and the amount of old stars in the galaxy--bigger black hole, bigger nucleus, more old stars. The largest black holes are in the supergiant elliptical galaxies like M87 below, which are basically all nucleus. The reason for this is complicated but is now becoming understood--it's cutting edge science right now (explanation upon request). This suggests that supermassive black holes date to the very beginning, not just the early days, of the universe. It may yet turn out that they are the first things to have come into existence after the Big Bang.